MUSEUM OF COMPARATIVE ZOOLOGY. 239 



United States under wood and stones. Its occurrence in wells is of course 

 accidental. 



" Three dragon-flies, two males and one female, taken at the mouth of Wil- 

 son's Cave, represent the Plathemis trimaculata De Geer, a swift-flying, light- 

 loving insect which is common about fresh water in most parts of the United 

 States. 



" Seven examples of Hygrotrechus remigis Say were collected in Wilson's 

 Cave, probably at no great distance from the entrance. These bugs prefer 

 shaded waters, and are commonly seen on the surface of pools under bridges 

 and culverts. Their eyes are relatively large, and they probably do not vol- 

 untarily visit regions entirely destitute of light. 



" From the mouth of Wilson's Cave are four examples of the common whir- 

 ligig beetle, Dineutes assimilis Aube, differing in no respect from examples col- 

 lected in other localities on open water. 



"A second beetle, also aquatic, is represented by one specimen labelled 

 ' Day's Cave, under rocks and stones in the mud.' It is a fine black Agabus, 

 probably A. suturalis Crotch, but without authentic examples of this species 

 for comparison it is hardly safe to make this determination final. From the 

 Californian A. lugeus Le Conte, to which it bears a close general resemblance, 

 it seems to differ chiefly in having the sides of the prothorax a little rounded, 

 and in having the basal margin sinuate. 



" The 'cricket' seems to be Ceuthophilus Sloanii Pack., of which its discov- 

 erer says in a recent paper : ' The species is at once known by the conspicuous 

 pale dorsal band which extends from between the eyes to the fourth seg- 

 ment behind, dilating slightly on the front edge of segments 2 to 4 ; the brown 

 portion has scattered pale dots on each side of the line,' etc. The specimens 

 are labelled ' From the water in Wilson's Cave.' 



" The remaining specimen is a fleshy, wrinkled dipterous larva, 7 mm. long 

 and 3 mm. in diameter, which was taken from a well." 



November 16, 1889. 



